There are now twice as many people as 50 years ago.
Photograph: Linh Pham/Getty Images

In a year of unrelenting political and climactic extremes, some of the best-read Guardian Cities stories looked at overpopulation and its impact on the environment and communities; others explored the reality of living in acute, road-melting heat.

We have also heard from underrepresented voices from urban areas ranging from Stoke-on-Trent to Atlanta, and found a truly walkable city. Here are the most-read Cities stories of 2018.

John Domokos dug deeper into the “Brexit heartland” of Stoke-on-Trent, often portrayed as a broken post-industrial city. His documentary series presents inspiring characters who want to change the narrative of this complex place.

By the turn of the next century, at least 10 cities are expected to have populations of over 50 million. What happens there in the next few decades will determine the environment and quality of life of the global population.

Melbourne seems to have been weighed down by its “most liveable city” title, not knowing whether it wants to be a global megacity or hang on to its charms and reputation as a liberal, progressive oasis. Guardian Australia’s Gay Alcorn reported on Melbourne’s “wobbly moment” as part of a week-long series on Australian cities.

Cities around Tesla’s massive battery factory in Nevada expected to reap the benefits. But critics say tax breaks have depleted public services, and the influx of high-paid tech workers has sent rents rocketing, leaving many residents dreaming of food, shelter and healthcare: “I can’t afford to move. Many times I can’t afford meat.”

As fiercely as Barcelona has fought against increasing tourism in the city, it has campaigned to welcome refugees. It seems its citizens increasingly see tourism, not immigration, as a threat to the city’s identity.

Since Donald Trump embarked on his political career, his surname appears to have become a liability, Arwa Mahdawi found. She spoke to previous tenants of his real estate empire who said his foray into politics has been disastrous for property prices.

“Leave about half the Earth’s surface mostly free of humans, so wild plants and animals can live there unimpeded as they did for so long before humans arrived. At a time when there are far more people alive than ever before, this plan might sound strange, even impossible. But it isn’t.”

A decade after Dubai’s fantasy archipelago of 300 artificial “countries” was scuppered by the financial crash, it is back in business. Oliver Wainwright visited The World and asked: has anybody learned anything?

It is the temperature at which human cells start to cook, animals suffer and air conditioners overload power grids. Once an urban anomaly, 50C is fast becoming reality. “You could see the physical change. Road surfaces started to melt, neighbourhoods went quiet because people didn’t go out and water vapour rose off the ground like a desert mirage.”

Jonathan Watts reported from Cape Town as the city faced its worst water shortage in almost 400 years. Supermarkets introduced limits for water bottle sales, hardware shops sold out of water tanks and pool covers, and even dehumidifiers were out of stock as the city prepared to be the first in the world to turn off its taps.

On a more positive note, the most-read Cities story focused on Pontevedra, a Galician city that has banned all but essential traffic. Instead of revving engines, its soundtrack is one of birdsong, the tinkle of coffee spoons, and humans talking to each other.